|In view of the size and complexity of the project and the distribution of the various activities among several geographical locations both onshore and offshore, the WLGP was sub-divided into (8) major project packages to be executed through individual contracts, which were awarded to several major EPC/EPIC contractors. This contracting strategy proved to be very successful and led to the execution of the project within the approved budget and in record time. Having completed the basic design and feed for the WLGP development drilling activities commenced in both fields during the year 2002.The project execution activities started in September 2002 with the Wafa Project.
The WLGP entered the production phase in September 2004 reaching the peak production in early 2006. Since then, the project has achieved record production rates of 323,000 Bbls of Oil Equivalents (BOE) per day on the 13th of December 2006.
Daily Production of 323,706 BOE
Western Libya Gas Project
The Western Libya Gas Project comprises a set of large Gas/Oil processing plants, worth more than 6 billion U.S. dollars in total investment, developed by Mellitah Gas a joint venture between National Oil Corporation of Libya and ENI Italy. These plants process raw gas and oil produced from the Wafa Onshore and Offshore Bahr Essalam Fields. The refined sales gas and other products, such as stabilised oil, condensate, propane, and butane are exported respectively via subsea pipeline to Italy and to Local and other markets via tankers and carriers.
The onshore section was divided in the following 3 main packages:
• Wafa Plants (Desert and Coastal)
• Mellitah Plant
The picture below depicts such division.
Wafa Plants (Desert and Coastal)
Wafa plants is one of the packages constituting the Western Libya Gas Project: JGC of Japan, in a joint venture with Tecnimont S.p.A. of Italy and Sofregaz S.A. of France, (JTS consortium) was named successful contractor on January 31,2002. Key dates are as per the below table.
|Construction Start||Sept. 2002||Sept. 2002|
|Oil Production Start Up||Sept. 2004||29 June 2004|
|Gas Production Start Up||Sept. 2004||2 Sept. 2004|
• Wafa Desert
Wafa Desert Plant, 525 Km SW of Tripoli comprises 37 Oil and Gas wells connected trough 207 Km gathering lines to the Central Plant.
This plant provides primary separation of gas and liquids. The gas treatment comprises of DEA-CO2 removal, 2 train dehydration, 2 train dew point control and export compression unit. The sales gas is transported via 32” pipeline to the Wafa Coastal Plant in Mellitah ready for the export. The Liquid treatment comprises of stabilization, separation and desalting units. The liquids are transported to the Wafa Coastal Plant via the 16” pipeline for further treatment. This plant includes also utility facilities, logistics and airstrip. The below pictures show the area plant at beginning and end of construction.
• Wafa Coastal
The Wafa Coastal Plant, 80 Km W of Tripoli, receives Gas and Liquids from Wafa Desert Plant. The gas is exported to Italy trough the Mellitah Gas Compression Station (Green Stream) via a 32” subsea pipeline and the Liquids are further treated and purified into commercial grade propane, butane, and stabilized Oil/Condensate, and are shipped using the Jetty and SPM export facilities.
The 525 Km onshore pipeline system comprises of 32” gas and 16” oil/condensates pipelines. Both pipelines run in parallel from Wafa Desert Plant to Mellitah (Wafa Coastal) where the sale gas is exported to Italy and the oil/condensate, after further treatment for LPG fractionation, is exported via Jetty and SPM facilities.
The pipeline consists of 16 valve and 4 pig trap stations. It also includes a leak detection and emergency shutdown system, as well as a fully integrated data transmission system.
The contract was awarded to CPECC of China on May 2002 and was completed on .
The pictures below show the pipeline installation and the piping route with LVS and PTS respectively.
The contract was awarded on 17/6/2002 and completed on 16/8/2004
This plant is part of the Mellitah Complex and treats the raw gas and un-stabilized condensate received from the Sabratha Platform, 110 Km offshore Tripoli, via 36”and 10” subsea pipelines. The process units include 3 trains gas sweetening, gas dehydration, sulphur recovery, stabilization, LPG fractioning, steam turbine power generation, solid/liquid sulphur storage and loading. As per Wafa, the treated gas is sent to Green Stream Compression Station and then to Italy. The contract was awarded to ABB Lummus/Snamprogetti/HDEC consortium on November 2002 and first gas was achieved in September 2005.
The pictures below show Mellitah site at beginning and end of construction.
The NC-41 Block offshore Libya covers an area between 30 km and 350 km from the Libyan coast in water depth ranging from 70 to 350 m.
The field development envisages gas exploitation from the ‘C’ hydrocarbon bearing structure with a target of 6 BSCM/year. This C-structure is 50 km long by 4 km wide in a water depth ranging from 160 to 210 m, with a WSW-ENE orientation, about 110-km from the Libyan coast.
The C structure has been divided into 2 areas:
|Area ||Number of wells |
The offshore section was divided in the following 3 main packages:
• Sabratha Platform
• Subsea System
• Gathering Pipelines and Export Trunklines
The picture below depicts such division.
This platform is designed to process gas and condensate from several reservoir areas. The Bahr Essalam fluids are produced on the Sabratha Platform (15 wells), and the others will be produced via subsea wells located at 25, 15 Km from the Sabratha platform.
After separation and dehydration of the fluids on the platform, the gas and condensate will be exported separately to shore approximately 110 km away for further processing.
The platform has been designed to guarantee a rate of 6 BSCM/Y of sale gas at the outlet of the onshore gas plant.
The Bahr Essalam Platform consists of:
• A launched and self upended jacket
• A single integrated deck containing
• A living quarter (including helideck) for 117 persons i normal operation.
• A flare boom
• A Fast Moving Work Over Rig (FMWR)
The contract was awarded on 18th June 2002 and first gas on 4th August 2005
The Project is primarily concerning the Western area gas field within the C structure tied back to the Central Platform via subsea flowlines.
A total of 11 subsea wells have been drilled in the Western area from two drill centres located within the field to give an optimum balance between the drilling cost, cost of flow line jumpers and minimising the risks associated with long reach highly deviated drilling. The ‘C’ Western subsea facilities comprised two 6-slot drilling templates with separately installed protective structures with manifolding pipe work (PSM). The pipeline end PSM with 5 wells and the midline PSM with 6 wells approximately 4.2 km apart, have been tied in daisy chain to NC-41 platform, 20 km away from the midline PSM.
All the wells (6+5) have been drilled through the pre drilling templates and completed with conventional subsea trees located within the PSMs.
The produced fluid from the Western area is transported to the process platform via subsea flowlines incorporating Subsea Isolation Valves (SSIV) at the platform end.
The control of the subsea wells are executed from the platform using multiplexed Electro-Hydraulic control system.
The contract was awarded on 31st July 2002 and ready for production was on 15/7/2005
Gathering Pipelines and Export Trunklines
The gathering pipeline and export trunklines are as per the following:
One 22” production line from ‘C’ Western to C Central B Platform.
One 8” test/production line from ‘C’ Western to C Central B Platform.
One 4” kill/service line from C Central B Platform to ‘C’ Western which shall be piggy backed on the 22” production line or on the 8” test/production line.
The mid PSM is approximately 20.5 km from C Central B Platform. End PSM is approximately 4 km away from Mid PSM.
One 36” dehydrated gas pipeline from C Central B platform to shore.
One 10” unstabilized condensate pipeline from C Central B platform to shore.
The pipelines are approximately 107km long.
Both lines were awarded on 4th November 2002 and were ready for gas in on 16th June 2005.